Question

2+4+6+8+.......+1000

Answer 1

Le definim in descompunere

2×1+2×2+2×3+....+2×500

Dam factor comun pe 2

2×(1+2+3+4+.....+500)

Aplicăm Suma lui Gauss

2×[n×(n+1):2]

2×[500×(500+1):2]

2×(500×501:2)

2×(250500:2)

2×125250

250500 raspuns